German Patent Disclosure Document DE-OS No. 27 55 926 to which U.S. Pat. No. 4,139,881, SHIMIZU et al., corresponds describes a circuit arrangement in which a flat plate such as a PC board with electric circuit tracks thereon is coupled to active and/or passive electronic components which do not have any projecting connecting tracks but, rather, plane or flat electrode surfaces at their external circumference for connection to conductors on the PC board. The electronic components may be capacitors, resistors, semiconductors, and the like, and are typically formed as rectangular blocks, with conductive bands or end caps at the terminal surfaces. The elements are frequently quite flat and are also referred to as chips as such.
Circuit arrangements of this type permit tightly positioned closely arranged location of components placed on both sides of a PC board. Discrete components having projecting wire ends are connected to the PC board from the free side thereof by extending the projecting pins through openings or bores to the side containing the conductive tracks. The conductive track side, also referred to as the solder side, then has the chip elements applied thereto. In accordance with customary attachment methods, the chip elements are first temporarily adhered by a drop of adhesive to the PC board and then secured to the PC board by dip-soldering in a bath of molten solder, simultaneously with connection the discrete elements having the extended wire portions passing through the PC board.
Application of adhesives to the PC board requires skill, since the elements are tiny. The quantity of adhesive to be applied must, on the one hand, be sufficient to securely retain the chip element in position until the solder step is completed; if, however, too much adhesive is applied, it may squeeze out from the application point upon pressing of the chip element against the PC board, and then can coat the conductive track connection, resulting in a poor solder joint, or failure of soldering at all.
The literature reference "Funkschau", 1976, issue 20, p. 855, describes a method to solder chip elements with plane flat terminal contacts to a substrate by inverting the PC board, so that the chip element will come to lie on the top side of a pre-tinned substrate, and then passing the PC board over a heater plate. The heat necessary to melt the solder must be applied through the PC board, i.e. the substrate. This system is not suitable for PC boards which are to have elements applied to both sides thereof, and is unsuitable for combination with dip-soldering or wave soldering.